Many microsurgical procedures require precision cutting and/or removal of various body tissues. For example, vitreoretinal surgery often requires the cutting, removal, dissection, delamination, coagulation, or other manipulation of delicate tissues such as the vitreous humor, traction bands, membranes, or the retina. The vitreous humor, or vitreous, is composed of numerous microscopic fibers that are often attached to the retina. Therefore, cutting, removal, or other manipulation of the vitreous must be done with great care to avoid traction on the retina, the separation of the retina from the choroid, a retinal tear, or, in the worst case, cutting and removal of the retina itself.
Microsurgical instruments, such as vitrectomy probes, fiber optic illuminators, infusion cannulas, aspiration probes, scissors, forceps, and lasers are typically utilized during vitreoretinal surgery. These devices are generally inserted through one or more surgical incisions in the sclera near the pars plana, which are called sclerotomies. One exemplary surgical probe includes a cutting blade disposed within a tubular probe needle. The cutting blade moves reciprocally within the probe needle relative to a second blade that is fixed within the tubular needle. The moving blade cuts material, e.g., vitreous humor, in a scissor-like motion adjacent the fixed blade.
To reduce potential damage to surgical sites and reduce recovery time, the size of the surgical incisions must be kept to a minimum. Accordingly, surgical probes are being designed in progressively smaller sizes to facilitate correspondingly smaller surgical incisions. As probe size decreases, cutting blades within the probes are decreased in size as well, thereby reducing blade strength and increasing the risk of fatigue or failure. Further, known mechanical forming methodologies such as grinding or machining are impractical at the small sizes typical of the blades, which typically have a maximum cross-sectional width of less than one (1) millimeter. Additionally, known forming processes are generally limited to blades having cross sections defining rectangular shapes, which prevents widening the blades to increase strength. Accordingly, current manufacturing methodologies and blade strength inhibit the degree to which probe needles may desirably be further reduced in size.